Noise cancellation system and method for amplifiers
AssigneeAnalog Devices, Inc.
InventorsRonald A. Kapusta, Colin Lyden, Haiyang Zhu
Life of this patent
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Abstract
An architecture of an integrated circuit allows for the canceling of noise sampled on a capacitor in the integrated circuit, after an input signal has already been sampled. Thermal noise correlated with an arbitrary input signal may be canceled after selectively controlling a plurality of switching devices during a sequence of clock phases. An auxiliary capacitor may be used to store a voltage equal to the thermal noise and enable the cancellation of the thermal noise from the sampled signal in conjunction with a noise cancellation unit.
Claims17
An integrated circuit for canceling thermal noise sampled during a sampling phase, the noise caused by a switch used to perform sampling of an input voltage, the integrated circuit comprising:
- an input connected to the input voltage;
- a capacitor storing a sample of the input voltage during the sampling phase, wherein the noise is also sampled on the capacitor;
- and
- an arrangement for noise cancellation, wherein the arrangement obtains a voltage corresponding to the noise sampled on the capacitor and cancels the noise during a hold phase using the obtained voltage.
An integrated circuit for canceling thermal noise sampled during a sampling phase, the noise caused by a switch used to perform sampling of an input voltage, the integrated circuit comprising:
- an input connected to the input voltage;
- a first capacitor storing a first sample of the input voltage during the sampling phase, wherein the noise is also sampled on the first capacitor;
- and
- a second capacitor storing a second sample, the value of the second sample being substantially equal to the value of the noise of the first sample.
A method for canceling thermal noise sampled during a sampling phase in an integrated circuit, the noise caused by a switch used to perform sampling of an input voltage, the method comprising:
- sampling the input voltage on a capacitor, the sampled input voltage including the noise;
- monitoring the noise of the sampled input voltage by a first arrangement that obtains the noise sampled on the capacitor;
- and
- canceling the noise during a hold phase by the first arrangement.
A method for canceling thermal noise sampled during sampling in an integrated circuit, the noise caused by a switch used to perform sampling of an input voltage, the method comprising:
- during a first phase, sampling the input voltage on a first capacitor, the sampled input voltage including the noise;
- during a second phase, outputting a voltage substantially equal to the noise through a buffer to a second capacitor;
- and
- during a third phase, transferring charge off of the first capacitor, wherein a charge corresponding to the sampled input voltage is transferred to a third capacitor, and wherein the voltage output to the second capacitor is used to prevent the noise from being transferred to the third capacitor.
A method for canceling a noise component sampled during sampling in an integrated circuit, the method comprising:
- during a first phase, sampling an input voltage on a first capacitor, the sampled input voltage including the noise;
- during a second phase, amplifying a voltage corresponding to the noise through a first amplifier to a second capacitor;
- during a third phase, performing the steps of:
- (i) transferring a signal charge off of the first capacitor;
- (ii) outputting a voltage potential at the top plate of the second capacitor through a second amplifier as an output of the integrated circuit;
- and
- (iii) generating a feedback loop to control a gain of the integrated circuit, wherein a voltage potential at the output of the integrated circuit correlates to the sampled input voltage without the noise, multiplied by a gain factor.
Dependencies are inferred from the claim text.